I was going to have a mechanic change the front seal on my 300CD, but I'm going to try it myself since I've already got a new seal in my garage and I'm in the process of changing my alternator, so I'm pretty much half way there.

Anyway, what is the process for accessing the seal once you remove the belts?? I noticed on the pulley that there is one large center nut/bolt surrounded by several smaller ones...

If you do not replace the dowel pins holding the balancer in place and torque up the big bolt properly it is quite likely that you'll end up with a damaged end on your crankshaft. This is quite a common write off your engine problem =>

Stretch, I think this is the second time you've tried to talk me out of this. Having now read through those links, I understand why. And boy am I glad you posted those links... my mechanic, unfortunately, is not a Mercedes specialist, so I doubt now that I could have any more confidence in him than than in my own work - and I'd hate for him to get in over his head.

So, I called the dealer to get an estimate. When I told them the year of my car (1983), they said they would need to have someone call me back...

When I re-installed the balancer on mine it was quite a job: I did have a flywheel lock (the job, in my opinion, is impossible without that), and luckily had a torque wrench that was up to the task. I had to brace the engine block against a wall with a 2x4 and had another guy helping to hold the back end of the block when I torqued in that main bolt. By the time you hit the full torque value on that thing, the whole block wants to roll over (keep in mind I'm using a 28-inch long torque wrench, so there's plenty of leverage).

Concerning the links talking about previous failures: I could easily see how someone could go to replace the front seal and then think they can just get that bolt "damn tight" and have it be good enough, especially since the balancer bolts on most American gasoline engines I've worked on are around 50 ft.lbs. There's just no way though; if you didn't have some gauge for the torque, most people would stop way short of the needed value.

Hell, I remember reading the torque value in the FSM and thinking it seemed incredibly high, but I did as it told. It is a pretty big bolt after all.

If you do not replace the dowel pins holding the balancer in place and torque up the big bolt properly it is quite likely that you'll end up with a damaged end on your crankshaft. This is quite a common write off your engine problem =>

There's another thread over on PP started by Diesel911 (300Dman over here) about this subject too but I can't find it for the life of me...

I have chimed in on a few Threads but have never pulled off the Crankshaft Damper before.

One of My comments is often that the Old Seal may have worn a groove into the Shaft. I can't recall if the Seal rides on the Shaft itself or that Sleeve.

If the Seal rids on the Shaft and it is grooved there is a Speedy Seal that has a sleeve the slides over the grooved Shaft. However, the kit comes with its own Seal.

I also ask a question a while back if anyone used a Vacuum Pump to vent the Crankcase vapors out of the Crankcase. Apparently People that race Cars use them. Since it reduces the Crankcase pressure or negates it altogether the claim is that the Seals cannot easily leak Oil out.

But, no one responded that they had used one so that is an experiment for someone else or for Me at some other time.

Back to the Crank Damper.
My comment on the other thread was something like "what do if you replace the Crank Damper Pins and they still slide in easily"?

And, the other comment was that when I did this sort of thing at work (not on Mercedes; I had worked in a Naval Ship Yard in the Diesel Shop) We drilled the Hole undersized and then used A Reamer to ream the Hole so the hole is straight.

The reason for that is that when you Drill Something by hand the Hole tends to wonder a little.

Another comment was that I the Holes did not look abnormally worn/elongated and the Pins were not I thought the inside and out side diameters could be roughed up and the Pins and holes coated with JB Weld Epoxy. Pins slid in and Damper Torqued down and excess Epoxy wiped off.
But, that is a purely experimental thing.

I also said that Loctite at one time made some sort of Red Jelly in a tube that was used for when you installed stuff on a shaft and it was slightly loose fit. The advantage there was that the Loctite is easy to release the Loctite by heating the Component with a Propane Torch while with the Epoxy it is more difficult to do that.

Comment on Mechanics. Most Mechanics are People who replace parts and a good one is good at troubleshooting what parts to replace.

However, they are not generally rebuilders of Parts.

So besides the skill level issues they are also not likely to have a "Flat Rate" Manual that is going to tell them what they should charge for drilling out the Crank Damper to oversieze Pins.

On the other end of the spectrum are hardcore Custom Car Guys that have all kinds of Machinist, Welding, Electrical and Body skills. Expensive and they normally don't deal with the more common repair stuff.

So I think a Person that pays attention to the Instructions is likely to do as good or better of a Job than an Indy Mechanic who has not done the Job before.
Unless the Indy takes a special interest in the Job He/She is not likely to send a lot of time reading and understanding the Instructions. The DIY Guy is going to spend a lot of time reading and asking questions.